Observing similar issues after kmod upgrade from version 26-3 to 26+20191223-1.
initramfs is built, despite of errors reported and all systems affected are bootable without problems for me. Temporary file claimed as missing (/var/tmp/mkinitramfs_iC46xD/lib/modules/5.4.8/modules.builtin.bin ) is on expected (temporary) location: mkinitramfs_iC46xD# ls -l lib/modules/5.4.8/modules.builtin.bin -rw------- 1 root root 6591 Jan 6 11:12 lib/modules/5.4.8/modules.builtin.bin
